Electric shavers are well known in which a number of rotary shaving units are combined into a shaving head. A particularly common design uses three shaving units in an equilateral triangular configuration. Each shaving unit comprises an external cutting element or cap and an internal cutting member or cutter. The cap is provided with a series of hair catching apertures or slots arranged substantially radially in one or more annular regions referred to as shaving tracks. The cap has an outer surface for engagement with the skin of a user and an inner surface which, in the shaving track region, is engaged by the cutter. The slots form cutting surfaces at the inner surface of the cap. The cutter carries cutter blades which terminate in cutting edges. Hairs entering the slots are cut or sheared between the cutting surfaces and the cutting edges. An example of such a shaving unit is disclosed in WO-2008/152590.
In designing a shaving unit, a primary consideration is to achieve as close a shave as possible. Nevertheless, it is well established within the shaving field that reducing the level of irritation suffered by a user during shaving is also desirable. A significant contributor to such irritation is skin damage caused by severing the top layers of skin by the cutting edges. The damage occurs due to the viscous properties of skin which cause the skin to bulge upwards (commonly referred to as skin doming) within the hair catching apertures or slots and enter the shaving area, where it may be cut or nipped between the cutter blades and the cutting surfaces.
It would therefore be desirable to alleviate this issue by providing a shaving unit with specific external and internal cutting member geometry to gently remove protruding skin from the shaving area and reduce the level of skin damage caused. It would also be desirable to still further reduce the external cutting element thickness in the cutting region in order to improve the closeness of the shave. It would also be desirable to provide larger hair catching apertures to improve hair catching efficiency.